1. Field of the Invention
The invention relates to flat bed knitting machines which can be programmed to produce prescribed designs in a fabric and has particular application to home knitting machines.
2. Description of the Prior Art
Programmable home knitting machines which pick up patterning instructions photoelectrically one row at a time from a program card on each knitting stroke of a carriage and utilize such instructions during the following knitting stroke are known and are exemplified by the machines of U.S. Pat. No. 3,885,405 and Japanese laid-open Pat. 85853/73. It is a disadvantage of such machines that they must pick up patterning instructions while the carriage moves at knitting speed, since this complicates the design problem and increases cost. In such machines a movable photoelectric reading head scans data on a program card which is stationary on the bed, and because of the speed at which the carriage may be moved high quality and therefore costly light emitting diodes (LED's) and phototransistors must be used in the reading head if the card is to be read accurately. It is also difficult to obtain accurate readings in such machines because there is no convenient way of shielding the programmed card from ambient light. Accuracy in the reading of a card on the bed by a reading head on the carriage is also difficult to obtain because of the liberal tolerances which must be provided between the carriage and the bed, the liberal tolerances being required to assure that any carriage or bed of any machine can be substituted for any other in the production line such that they may be produced at a reasonable cost.